Personality: what makes us who we are?

"I'm cheerful, outgoing, funny, and nice."

When people are asked to describe their personality, they usually pick simple adjectives to try to come up with a suitable explanation for a concept that defines our whole being. With a concept so broad, it's not surprising that personality has been a difficult area for psychologists to study.

One approach to examining personality is through behavior-genetic studies. A behavior-genetic approach to personality looks at three main influences:

1. Genetic factors
2. Shared environmental factors
3. Nonshared environmental factors

Shared environmental factors are experiences in families that make people more alike. For example, making all siblings more outgoing by encouraging interaction with others. Nonshared environmental factors make individuals less alike, such as one sibling receiving more freedom than another.

In studies involving identical twins that were separated at birth, different pairs of twins were revisited as adults and found to share similar personalities as their twin. The results of these studies show that some personality traits, such as impulsiveness and anxiety, are influenced by genetics.

So, what is it that makes us who we are? Although some explanations have been determined, we are still currently unable to provide clear, precise reasons to explain why we develop specific personalities. Is it possible that we will one day be able to categorize and determine the causes of all aspects of a person's personality?